The present invention relates to a gas washing device of the type including a permeable gas sink, a gas inlet for supplying gas through the sink to a molten metal container, a layer of gas permeable material located between the sink and the gas inlet, and a gas flow meter upstream of the gas inlet.
This general type of gas washing device is disclosed in the journal "Giesserei 72", 1985, No. 6. The layer of gas permeable material on which the gas sink rests is formed by loose, coarse, monolithic lining material. When the material of the gas sink all is used, then the molten metal passes into such layer, and this avoids a breakthrough of the molten metal upon consumption of the gas sink.
DE-OS No. 32 40 097 also discloses a layer of granular fill material. This fill material has a melting point below the temperature of the molten metal. This has the effect that when the gas sink is consumed and molten metal passes into the fill material, a closure is formed which prevents molten metal from breaking through. This arrangement however also interrupts the gas washing operation.
EP No. 0 082 078 A1 discloses a gas sink including electrodes to provide an electric monitoring of the extent of wear of the gas sink.